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Lee KT, Liao HS, Hsieh MH. Glutamine Metabolism, Sensing and Signaling in Plants. PLANT & CELL PHYSIOLOGY 2023; 64:1466-1481. [PMID: 37243703 DOI: 10.1093/pcp/pcad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/23/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
Glutamine (Gln) is the first amino acid synthesized in nitrogen (N) assimilation in plants. Gln synthetase (GS), converting glutamate (Glu) and NH4+ into Gln at the expense of ATP, is one of the oldest enzymes in all life domains. Plants have multiple GS isoenzymes that work individually or cooperatively to ensure that the Gln supply is sufficient for plant growth and development under various conditions. Gln is a building block for protein synthesis and an N-donor for the biosynthesis of amino acids, nucleic acids, amino sugars and vitamin B coenzymes. Most reactions using Gln as an N-donor are catalyzed by Gln amidotransferase (GAT) that hydrolyzes Gln to Glu and transfers the amido group of Gln to an acceptor substrate. Several GAT domain-containing proteins of unknown function in the reference plant Arabidopsis thaliana suggest that some metabolic fates of Gln have yet to be identified in plants. In addition to metabolism, Gln signaling has emerged in recent years. The N regulatory protein PII senses Gln to regulate arginine biosynthesis in plants. Gln promotes somatic embryogenesis and shoot organogenesis with unknown mechanisms. Exogenous Gln has been implicated in activating stress and defense responses in plants. Likely, Gln signaling is responsible for some of the new Gln functions in plants.
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Affiliation(s)
- Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
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2
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Liu HJ, Yang ZL, Ren LL, Wang YM, Wang X, Qian TT. Functional Divergence of the Glutamine Phosphoribosyl Pyrophosphate Amidotransferase (ASE) Gene Family in Arabidopsis. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Cao X, Du B, Han F, Zhou Y, Ren J, Wang W, Chen Z, Zhang Y. Crystal Structure of the Chloroplastic Glutamine Phosphoribosylpyrophosphate Amidotransferase GPRAT2 From Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:157. [PMID: 32174940 PMCID: PMC7056826 DOI: 10.3389/fpls.2020.00157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 01/31/2020] [Indexed: 05/03/2023]
Abstract
Chloroplastic glutamine phosphoribosylpyrophosphate amidotransferase (GPRATase) catalyzes the first committed step of de novo purine biosynthesis in Arabidopsis thaliana, and DAS734 is a direct and specific inhibitor of AtGPRAT, with phytotoxic effects similar to the leaf beaching phenotypes of known AtGPRAT genetic mutants, especially cia1 and atd2. However, the structure of AtGPRAT and the inhibition mode of DAS734 still remain poorly understood. In this study, we solved the structure of AtGPRAT2, which revealed structural differences between AtGPRAT2 and bacterial enzymes. Kinetics assay demonstrated that DAS734 behaves as a competitive inhibitor for the substrate phosphoribosyl pyrophosphate (PRPP) of AtGPRAT2. Docking studies showed that DAS734 forms electrostatic interactions with R264 and hydrophobic interactions with several residues, which was verified by binding assays. Collectively, our study provides important insights into the inhibition mechanism of DAS734 to AtGPRAT2 and sheds light on future studies into further development of more potent herbicides targeting Arabidopsis GPRATases.
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Affiliation(s)
- Xueli Cao
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
| | - Bowen Du
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
| | - Fengjiao Han
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
| | - Yu Zhou
- Department of Computational Chemistry, National Institute of Biological Sciences, Beijing, China
| | - Junhui Ren
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
| | - Wenhe Wang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
| | - Zeliang Chen
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Yi Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, China
- *Correspondence: Yi Zhang,
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4
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Davies JP, Christensen CA. Developing Transgenic Agronomic Traits for Crops: Targets, Methods, and Challenges. Methods Mol Biol 2019; 1864:343-365. [PMID: 30415346 DOI: 10.1007/978-1-4939-8778-8_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The last two decades have witnessed a surge of investment by the agricultural biotechnology industry in the development of transgenic agronomic traits. These are traits that improve yield performance by modifying endogenous physiological processes such as energy capture, nutrient utilization, and stress tolerance. In this chapter we provide a foundation for understanding these fundamental processes and then outline approaches that have been taken to use this knowledge for yield improvement. We characterize the current status of product development pipelines in the industry and illustrate the trait discovery process with three important examples-bacterial cold-shock proteins, alanine aminotransferase, and auxin-regulated genes. The challenges with developing and commercializing an agronomic trait product are discussed.
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Affiliation(s)
- John P Davies
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Indianapolis, IN, USA.
| | - Cory A Christensen
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Indianapolis, IN, USA
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5
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Fan X, Xu J, Lavoie M, Peijnenburg WJGM, Zhu Y, Lu T, Fu Z, Zhu T, Qian H. Multiwall carbon nanotubes modulate paraquat toxicity in Arabidopsis thaliana. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 233:633-641. [PMID: 29107903 DOI: 10.1016/j.envpol.2017.10.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/05/2017] [Accepted: 10/28/2017] [Indexed: 05/21/2023]
Abstract
Carbon nanotubes can be either toxic or beneficial to plant growth and can also modulate toxicity of organic contaminants through surface sorption. The complex interacting toxic effects of carbon nanotubes and organic contaminants in plants have received little attention in the literature to date. In this study, the toxicity of multiwall carbon nanotubes (MWCNT, 50 mg/L) and paraquat (MV, 0.82 mg/L), separately or in combination, were evaluated at the physiological and the proteomic level in Arabidopsis thaliana for 7-14 days. The results revealed that the exposure to MWCNT had no inhibitory effect on the growth of shoots and leaves. Rather, MWCNT stimulated the relative electron transport rate and the effective photochemical quantum yield of PSII value as compared to the control by around 12% and lateral root production up to nearly 4-fold as compared to the control. The protective effect of MWCNT on MV toxicity on the root surface area could be quantitatively explained by the extent of MV adsorption on MWCNT and was related to stimulation of photosynthesis, antioxidant protection and number and area of lateral roots which in turn helped nutrient assimilation. The influence of MWCNT and MV on photosynthesis and oxidative stress at the physiological level was consistent with the proteomics analysis, with various over-expressed photosynthesis-related proteins (by more than 2 folds) and various under-expressed oxidative stress related proteins (by about 2-3 folds). This study brings new insights into the interactive effects of two xenobiotics (MWCNT and MV) on the physiology of a model plant.
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Affiliation(s)
- Xiaoji Fan
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Jiahui Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Michel Lavoie
- Quebec-Ocean and Takuvik Joint International Research Unit, Université Laval, Québec, Canada
| | - W J G M Peijnenburg
- Institute of Environmental Sciences (CML), Leiden University, 2300 RA, Leiden, The Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, P.O. Box 1, Bilthoven, The Netherlands
| | - Youchao Zhu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Tingheng Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China.
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Chuprov–Netochin R, Neskorodov Y, Marusich E, Mishutkina Y, Volynchuk P, Leonov S, Skryabin K, Ivashenko A, Palme K, Touraev A. Novel small molecule modulators of plant growth and development identified by high-content screening with plant pollen. BMC PLANT BIOLOGY 2016; 16:192. [PMID: 27596094 PMCID: PMC5011872 DOI: 10.1186/s12870-016-0875-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 08/16/2016] [Indexed: 05/03/2023]
Abstract
BACKGROUND Small synthetic molecules provide valuable tools to agricultural biotechnology to circumvent the need for genetic engineering and provide unique benefits to modulate plant growth and development. RESULTS We developed a method to explore molecular mechanisms of plant growth by high-throughput phenotypic screening of haploid populations of pollen cells. These cells rapidly germinate to develop pollen tubes. Compounds acting as growth inhibitors or stimulators of pollen tube growth are identified in a screen lasting not longer than 8 h high-lighting the potential broad applicability of this assay to prioritize chemicals for future mechanism focused investigations in plants. We identified 65 chemical compounds that influenced pollen development. We demonstrated the usefulness of the identified compounds as promotors or inhibitors of tobacco and Arabidopsis thaliana seed growth. When 7 days old seedlings were grown in the presence of these chemicals twenty two of these compounds caused a reduction in Arabidopsis root length in the range from 4.76 to 49.20 % when compared to controls grown in the absence of the chemicals. Two of the chemicals sharing structural homology with thiazolidines stimulated root growth and increased root length by 129.23 and 119.09 %, respectively. The pollen tube growth stimulating compound (S-02) belongs to benzazepin-type chemicals and increased Arabidopsis root length by 126.24 %. CONCLUSIONS In this study we demonstrate the usefulness of plant pollen tube based assay for screening small chemical compound libraries for new biologically active compounds. The pollen tubes represent an ultra-rapid screening tool with which even large compound libraries can be analyzed in very short time intervals. The broadly applicable high-throughput protocol is suitable for automated phenotypic screening of germinating pollen resulting in combination with seed germination assays in identification of plant growth inhibitors and stimulators.
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Affiliation(s)
- Roman Chuprov–Netochin
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
| | - Yaroslav Neskorodov
- Research Centerof Biotechnology of the Russian Academy of Science, 117312 Moscow, Russian Federation
| | - Elena Marusich
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
| | - Yana Mishutkina
- Research Centerof Biotechnology of the Russian Academy of Science, 117312 Moscow, Russian Federation
| | - Polina Volynchuk
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
| | - Sergey Leonov
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
| | - Konstantin Skryabin
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
- Research Centerof Biotechnology of the Russian Academy of Science, 117312 Moscow, Russian Federation
- Lomonosov Moscow State University, 119991 Moscow, Russian Federation
| | - Andrey Ivashenko
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
| | - Klaus Palme
- Faculty of Biology; BIOSS Centre for Biological Signaling Studies; ZBSA Centre for Biological Systems Analysis, University of Freiburg, Schänzlestr.1, 79104 Freiburg, Germany
| | - Alisher Touraev
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow region Russian Federation
- Lomonosov Moscow State University, 119991 Moscow, Russian Federation
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7
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Coleto I, Trenas AT, Erban A, Kopka J, Pineda M, Alamillo JM. Functional specialization of one copy of glutamine phosphoribosyl pyrophosphate amidotransferase in ureide production from symbiotically fixed nitrogen in Phaseolus vulgaris. PLANT, CELL & ENVIRONMENT 2016; 39:1767-1779. [PMID: 27004600 DOI: 10.1111/pce.12743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Purines are essential molecules formed in a highly regulated pathway in all organisms. In tropical legumes, the nitrogen fixed in the nodules is used to generate ureides through the oxidation of de novo synthesized purines. Glutamine phosphoribosyl pyrophosphate amidotransferase (PRAT) catalyses the first committed step of de novo purine synthesis. In Phaseolus vulgaris there are three genes coding for PRAT. The three full-length sequences, which are intron-less genes, were cloned, and their expression levels were determined under conditions that affect the synthesis of purines. One of the three genes, PvPRAT3, is highly expressed in nodules and protein amount and enzymatic activity in these tissues correlate with nitrogen fixation activity. Inhibition of PvPRAT3 gene expression by RNAi-silencing and subsequent metabolomic analysis of the transformed roots shows that PvPRAT3 is essential for the synthesis of ureides in P. vulgaris nodules.
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Affiliation(s)
- Inmaculada Coleto
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Almudena T Trenas
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Alexander Erban
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Joachim Kopka
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Manuel Pineda
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Josefa M Alamillo
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas. Campus de Excelencia Internacional Agroalimentario, CEIA3. Campus de Rabanales, Edif. Severo Ochoa, Universidad de Córdoba, 14071, Córdoba, Spain
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8
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Yang Z, Shang Z, Wang L, Lu Q, Wen X, Chi W, Zhang L, Lu C. Purine biosynthetic enzyme ATase2 is involved in the regulation of early chloroplast development and chloroplast gene expression in Arabidopsis. PHOTOSYNTHESIS RESEARCH 2015; 126:285-300. [PMID: 25837856 DOI: 10.1007/s11120-015-0131-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/24/2015] [Indexed: 05/14/2023]
Abstract
To investigate the molecular mechanism of chloroplast biogenesis and development, we characterized an Arabidopsis mutant (dg169, delayed greening 169) which showed growth retardation and delayed greening phenotype in leaves. Newly emerged chlorotic leaves recovered gradually with leaf development in the mutant, and the mature leaves showed similar phenotype to those of wild-typewild-type plants. Compared with wild-type, the chloroplasts were oval-shaped and smaller and the thylakoid membranes were less abundant in yellow section of young leaves of dg169. In addition, the functions of photosystem II (PSII) and photosystem I (PSI) were also impaired. Furthermore, the amount of core subunits of PSII and PSI, as well as PSII and PSI complexes reduced in yellow section of young leaves of dg169. Map-based positional cloning identified that phenotype of dg169 was attributed to a point mutation of ATase2 which converts the conserved Ile-155 residue to Asn. ATase2 catalyzes the first step of de novo purine biosynthesis. This mutation resulted in impaired purine synthesis and a significant decrease in ATP, ADP, GTP and GDP contents. The analysis of ATase2-GFP protein fusion showed that ATase2 was localized to nucleoid of chloroplasts. Our results further demonstrated that the levels of PEP-dependent transcripts in yellow section of young leaves of dg169 were decreased while NEP-dependent and both PEP- and NEP-dependent transcripts and chloroplast DNA replications were increased. The results in this study suggest that ATase2 plays an essential role in early chloroplast development through maintaining PEP function.
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Affiliation(s)
- Zhipan Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
| | - Zengzhen Shang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qingtao Lu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaogang Wen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Congming Lu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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9
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Serrano M, Kombrink E, Meesters C. Considerations for designing chemical screening strategies in plant biology. FRONTIERS IN PLANT SCIENCE 2015; 6:131. [PMID: 25904921 PMCID: PMC4389374 DOI: 10.3389/fpls.2015.00131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/18/2015] [Indexed: 05/03/2023]
Abstract
Traditionally, biologists regularly used classical genetic approaches to characterize and dissect plant processes. However, this strategy is often impaired by redundancy, lethality or pleiotropy of gene functions, which prevent the isolation of viable mutants. The chemical genetic approach has been recognized as an alternative experimental strategy, which has the potential to circumvent these problems. It relies on the capacity of small molecules to modify biological processes by specific binding to protein target(s), thereby conditionally modifying protein function(s), which phenotypically resemble mutation(s) of the encoding gene(s). A successful chemical screening campaign comprises three equally important elements: (1) a reliable, robust, and quantitative bioassay, which allows to distinguish between potent and less potent compounds, (2) a rigorous validation process for candidate compounds to establish their selectivity, and (3) an experimental strategy for elucidating a compound's mode of action and molecular target. In this review we will discuss details of this general strategy and additional aspects that deserve consideration in order to take full advantage of the power provided by the chemical approach to plant biology. In addition, we will highlight some success stories of recent chemical screenings in plant systems, which may serve as teaching examples for the implementation of future chemical biology projects.
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Affiliation(s)
- Mario Serrano
- Plant Biology, Department of Biology, University of FribourgFribourg, Switzerland
| | - Erich Kombrink
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding ResearchKöln, Germany
| | - Christian Meesters
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding ResearchKöln, Germany
- Department of Chemical Biology, Faculty of Biology, Center for Medical Biotechnology, University of Duisburg-EssenEssen, Germany
- *Correspondence: Christian Meesters, Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Köln, Germany
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10
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Meesters C, Mönig T, Oeljeklaus J, Krahn D, Westfall CS, Hause B, Jez JM, Kaiser M, Kombrink E. A chemical inhibitor of jasmonate signaling targets JAR1 in Arabidopsis thaliana. Nat Chem Biol 2014; 10:830-6. [PMID: 25129030 DOI: 10.1038/nchembio.1591] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 06/12/2014] [Indexed: 12/11/2022]
Abstract
Jasmonates are lipid-derived plant hormones that regulate plant defenses and numerous developmental processes. Although the biosynthesis and molecular function of the most active form of the hormone, (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), have been unraveled, it remains poorly understood how the diversity of bioactive jasmonates regulates such a multitude of plant responses. Bioactive analogs have been used as chemical tools to interrogate the diverse and dynamic processes of jasmonate action. By contrast, small molecules impairing jasmonate functions are currently unknown. Here, we report on jarin-1 as what is to our knowledge the first small-molecule inhibitor of jasmonate responses that was identified in a chemical screen using Arabidopsis thaliana. Jarin-1 impairs the activity of JA-Ile synthetase, thereby preventing the synthesis of the active hormone, JA-Ile, whereas closely related enzymes are not affected. Thus, jarin-1 may serve as a useful chemical tool in search for missing regulatory components and further dissection of the complex jasmonate signaling networks.
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Affiliation(s)
- Christian Meesters
- 1] Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Köln, Germany. [2] Center for Medical Biotechnology, Department of Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Timon Mönig
- Center for Medical Biotechnology, Department of Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Julian Oeljeklaus
- Center for Medical Biotechnology, Department of Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Daniel Krahn
- Center for Medical Biotechnology, Department of Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Corey S Westfall
- Department of Biology, Washington University, St. Louis, Missouri, USA
| | - Bettina Hause
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany
| | - Joseph M Jez
- Department of Biology, Washington University, St. Louis, Missouri, USA
| | - Markus Kaiser
- Center for Medical Biotechnology, Department of Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Erich Kombrink
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Köln, Germany
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11
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Abstract
Chemical genetics utilizes small molecules to perturb biological processes. Unlike conventional genetics methods, which involve the alteration of genetic information mostly with lasting effects, chemical genetics allows temporary and reversible alterations of biological processes. Furthermore, it enables the alteration of biological processes in a dose-dependent manner, providing an advantage over conventional genetics. In the present chapter, the general procedures of forward chemical genetic screening are described. Forward chemical genetic screening can be performed in three steps. The first step involves the identification of small molecules that induce phenotypic or physiological changes in a biological system from a chemical library. In the second step, cellular targets that interact with the isolated chemical, which are mostly proteins, are identified. Although several methods can be applied in the second step, the most common one is affinity pull-down assay using a target protein that binds to the isolated compound. However, affinity pull-down of a target protein is a formidable barrier in forward chemical genetics. We introduced a tagged chemical library approach that significantly facilitates the identification of target proteins. The third step consists of the validation of the target protein, which should include the assessment of target specificity. This step is critical because small molecules often show pleiotropic effects due to low specificity. The specificity test may include a competition assay using cold competitors and a genetic study using mutants or transgenic lines modified for the cellular target.
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12
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Dejonghe W, Russinova E. Target identification strategies in plant chemical biology. FRONTIERS IN PLANT SCIENCE 2014; 5:352. [PMID: 25104953 PMCID: PMC4109434 DOI: 10.3389/fpls.2014.00352] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/30/2014] [Indexed: 05/03/2023]
Abstract
The current needs to understand gene function in plant biology increasingly require more dynamic and conditional approaches opposed to classic genetic strategies. Gene redundancy and lethality can substantially complicate research, which might be solved by applying a chemical genetics approach. Now understood as the study of small molecules and their effect on biological systems with subsequent target identification, chemical genetics is a fast developing field with a strong history in pharmaceutical research and drug discovery. In plant biology however, chemical genetics is still largely in the starting blocks, with most studies relying on forward genetics and phenotypic analysis for target identification, whereas studies including direct target identification are limited. Here, we provide an overview of recent advances in chemical genetics in plant biology with a focus on target identification. Furthermore, we discuss different strategies for direct target identification and the possibilities and challenges for plant biology.
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Affiliation(s)
- Wim Dejonghe
- Department of Plant Systems Biology, VIBGhent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent UniversityGhent, Belgium
| | - Eugenia Russinova
- Department of Plant Systems Biology, VIBGhent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent UniversityGhent, Belgium
- *Correspondence: Eugenia Russinova, Department of Plant Systems Biology and Department of Plant Biotechnology and Bioinformatics, VIB-Ghent University, Technologiepark 927, 9052 Ghent, Belgium e-mail:
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13
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Walsh TA. Early stage hit triage for plant chemical genetic screens and target site identification. Methods Mol Biol 2014; 1056:191-199. [PMID: 24306874 DOI: 10.1007/978-1-62703-592-7_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The increasing use of plant biological screens of large compound libraries to discover informative chemical probes for plant chemical genetics requires efficient methods for hit selection and advancement. Downstream target identification and validation studies with selected chemistries can also be resource-intensive and have a significant failure rate. Several steps and considerations for early stage hit triage are outlined to increase the probability of success that downstream studies with the chemical probe will be robust and productive, especially for target site discovery. Conversely, problematic compounds can be shelved or avoided entirely, saving time and resources. These steps include assessment of compound availability, purity, stability and solubility; determination of the biological dose-response; early and iterative evaluation of analogs; avoidance of promiscuous "frequent-hitters"; consideration of physicochemical parameters affecting compound bioavailability and mobility, use of "low-barrier" biological testing systems; and assessing the potential for compound metabolism or bioconversion.
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Affiliation(s)
- Terence A Walsh
- Discovery Research, Dow AgroSciences LLC, Indianapolis, IN, USA
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Tresch S. Strategies and future trends to identify the mode of action of phytotoxic compounds. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 212:60-71. [PMID: 24094055 DOI: 10.1016/j.plantsci.2013.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 05/09/2023]
Abstract
Small molecules affecting plant processes have been widely used as probes to study basic physiology. In agricultural practices some of these molecules have served as herbicides or plant growth regulators. Historically, most of the compounds were identified in large screens by the agrochemical industry, but also as phytoactive natural products. More recently, novel phytoactive compounds originated from academic research by chemical screens performed to induce specific phenotypes of interest. In the present review different approaches were evaluated for the identification of the mode of action (MoA) of phytoactive compounds. Based on the methodologies used for MoA identification, three approaches are differentiated: a phenotyping approach, an approach based on a genetic screen and a biochemical screening approach. Target sites of compounds targeting primary or secondary metabolism were identified most successfully with a phenotyping approach. Target sites for compounds that influence cell structure, such as cell wall biosynthesis or the cytoskeleton, or compounds that interact with the hormone system, were in most cases discovered by using a genetic approach. Examples showing the strengths and weaknesses of the different approaches are discussed in detail. Additionally, new techniques that could contribute to future MoA identification projects are reviewed. In particular, next-generation sequencing techniques may be used for the fast-forward mapping of mutants identified in genetic screens. Finally, a revised three-tiered approach for the MoA identification of phytoactive compounds is proposed. The approach consists of a 1st tier, which addresses compound stability, uniformity of effects in different species, general cytotoxicity and the effect on common processes such as transcription and translation. Advanced studies based on these findings initiate the 2nd tier MoA characterization, either with further phenotypic characterization, starting a genetic screen or establishing a biochemical screen. At the 3rd tier, enzyme assays or protein affinity studies should show the activity of the compound on the hypothesized target and should associate the in vitro effects with the in vivo profile of the compound.
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Affiliation(s)
- Stefan Tresch
- BASF SE, Crop Protection, Speyerer Str. 2, 67117 Limburgerhof, Germany.
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Chen YT, Shen CH, Lin WD, Chu HA, Huang BL, Kuo CI, Yeh KW, Huang LC, Chang IF. Small RNAs of Sequoia sempervirens during rejuvenation and phase change. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:27-36. [PMID: 23016572 DOI: 10.1111/j.1438-8677.2012.00622.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work, the population of small RNAs (sRNAs) was studied in the gymnosperm Sequoia sempervirens during phase changes, specifically in the juvenile, adult and rejuvenated plants obtained in vitro. The potential target genes of Sequoia sRNAs were predicted through bioinformatics. Rejuvenation is a pivotal process in woody plants that enables them to regain their growth potential, which results in the recovery of physiologic and molecular characteristics that were lost when the juveniles mature into adult plants. The results from the five repeated graftings of juvenile, adult and rejuvenated plants in vitro showed that sRNAs could be classified into structural RNAs (Group I), small interfering RNAs (Group II), annotated microRNAs (Group III, and unannotated sRNAs (Group IV). The results indicate that only 573 among 15,485,415 sRNAs (Groups III and IV) had significantly different expression patterns associated with rejuvenation and phase change. A total of 215 sRNAs exhibited up-regulated expression patterns in adult shoots, and 358 sRNAs were down-regulated. Expression profiling and prediction of possible target genes of these unique small RNAs indicate possible functions in the control of photosynthetic efficiency and rooting competence abundance during plant rejuvenation. Moreover, the increase in SsmiR156 and decrease in SsmiR172 during plant rejuvenation suggested that these two microRNAs extensively affect phase transition.
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Affiliation(s)
- Y-T Chen
- Institute of Genomics and Bioinformatics, Agricultural Biotechnology Centre, National Chung Hsing University, Tauchung, Taiwan
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Sergeant MJ, Harrison PJ, Jenkins R, Moran GR, Bugg TDH, Thompson AJ. Phytotoxic effects of selected N-benzyl-benzoylhydroxamic acid metallo-oxygenase inhibitors: investigation into mechanism of action. NEW J CHEM 2013. [DOI: 10.1039/c3nj00491k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Rosar C, Kanonenberg K, Nanda AM, Mielewczik M, Bräutigam A, Novák O, Strnad M, Walter A, Weber APM. The leaf reticulate mutant dov1 is impaired in the first step of purine metabolism. MOLECULAR PLANT 2012; 5:1227-41. [PMID: 22532604 DOI: 10.1093/mp/sss045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A series of reticulated Arabidopsis thaliana mutants were previously described. All mutants show a reticulate leaf pattern, namely green veins on a pale leaf lamina. They have an aberrant mesophyll structure but an intact layer of bundle sheath cells around the veins. Here, we unravel the function of the previously described reticulated EMS-mutant dov1 (differential development of vascular associated cells 1). By positional cloning, we identified the mutated gene, which encodes glutamine phosphoribosyl pyrophosphate aminotransferase 2 (ATase2), an enzyme catalyzing the first step of purine nucleotide biosynthesis. dov1 is allelic to the previously characterized cia1-2 mutant that was isolated in a screen for mutants with impaired chloroplast protein import. We show that purine-derived total cytokinins are lowered in dov1 and crosses with phytohormone reporter lines revealed differential reporter activity patterns in dov1. Metabolite profiling unraveled that amino acids that are involved in purine biosynthesis are increased in dov1. This study identified the molecular basis of an established mutant line, which has the potential for further investigation of the interaction between metabolism and leaf development.
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Affiliation(s)
- Christian Rosar
- Institute for Plant Biochemistry, Heinrich-Heine-Universität, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
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Grossmann K, Christiansen N, Looser R, Tresch S, Hutzler J, Pollmann S, Ehrhardt T. Physionomics and metabolomics-two key approaches in herbicidal mode of action discovery. PEST MANAGEMENT SCIENCE 2012; 68:494-504. [PMID: 22076706 DOI: 10.1002/ps.2300] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/05/2011] [Accepted: 08/11/2011] [Indexed: 05/26/2023]
Abstract
BACKGROUND For novel herbicides identified in greenhouse screens, efficient research is important to discover and chemically optimise new leads with new modes of action (MoAs). RESULTS The metabolic and physiological response pattern to a herbicide can be viewed as the result of changes elicited in the molecular and biochemical process chain. These response patterns are diagnostic of a herbicide's MoA. At the starting point of MoA characterisation, an array of bioassays is used for comprehensive physiological profiling of herbicide effects. This physionomics approach enables discrimination between known, novel or multiple MoAs of a compound and provides a first clue to a new MoA. Metabolic profiling is performed with the use of treated Lemna paucicostata plants. After plant extraction and chromatography and mass spectrometry, changes in levels of approximately 200 identified and 300 unknown analytes are quantified. Check for known MoA assignment is performed by multivariate statistical data analyses. Distinct metabolite changes, which can direct to an affected enzymatic step, are visualised in a biochemical pathway view. Subsequent target identification includes metabolite feeding and molecular, biochemical and microscopic methods. CONCLUSION The value of this cascade strategy is exemplified by new herbicides with MoAs in plastoquinone, auxin or very-long-chain fatty acid synthesis.
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Affiliation(s)
- Klaus Grossmann
- BASF Agricultural Centre Limburgerhof, Limburgerhof, Germany.
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Hicks GR, Raikhel NV. Small molecules present large opportunities in plant biology. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:261-82. [PMID: 22404475 DOI: 10.1146/annurev-arplant-042811-105456] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Since the introduction of chemical genomics to plant biology as a tool for basic research, the field has advanced significantly. There are now examples of important basic discoveries that demonstrate the power and untapped potential of this approach. Given the combination of protein and small-molecule complexity, new phenotypes can be described through the perturbation of cellular functions that can be linked to growth and developmental phenotypes. There are now clear examples of overcoming functional redundancy in plants to dissect molecular mechanisms or critical pathways such as hormone signaling and dynamic intracellular processes. Owing to ongoing advances, including more sophisticated high-content screening and rapid approaches for target identification, the field is beginning to move forward. However, there are also challenges to improve automation, imaging, and analysis and provide chemical biology resources to the broader plant biology community.
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Affiliation(s)
- Glenn R Hicks
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
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Woo NS, Gordon MJ, Graham SR, Rossel JB, Badger MR, Pogson BJ. A mutation in the purine biosynthetic enzyme ATASE2 impacts high light signalling and acclimation responses in green and chlorotic sectors of Arabidopsis leaves. FUNCTIONAL PLANT BIOLOGY : FPB 2011; 38:401-419. [PMID: 32480896 DOI: 10.1071/fp10218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 03/22/2011] [Indexed: 05/14/2023]
Abstract
In this report, we investigate the altered APX2 expression 13 (alx13) mutation of Arabidopsis thaliana, a mutation in glutamine phosphoribosyl pyrophosphate amidotransferase 2 (ATASE2), the primary isoform of the enzyme mediating the first committed step of purine biosynthesis. Light-dependent leaf variegation was exhibited by alx13 plants, with partial shading of alx13 rosettes revealing that the development of chlorosis in emerging leaves is influenced by the growth irradiance of established leaves. Chlorotic sectors arose from emerging green alx13 leaves during a phase of rapid cell division and expansion, which shows that each new cell's fate is independent of its progenitor. In conjunction with the variegated phenotype, alx13 plants showed altered high light stress responses, including changed expression of genes encoding proteins with antioxidative functions, impaired anthocyanin production and over-accumulation of reactive oxygen species. These characteristics were observed in both photosynthetically-normal green tissues and chlorotic tissues. Chlorotic tissues of alx13 leaves accumulated mRNAs of nuclear-encoded photosynthesis genes that are repressed in other variegated mutants of Arabidopsis. Thus, defective purine biosynthesis impairs chloroplast biogenesis in a light-dependent manner and alters the induction of high light stress pathways and nuclear-encoded photosynthesis genes.
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Affiliation(s)
- Nick S Woo
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Matthew J Gordon
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Stephen R Graham
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Jan Bart Rossel
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Murray R Badger
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Barry J Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
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Hicks GR, Raikhel NV. Advances in dissecting endomembrane trafficking with small molecules. CURRENT OPINION IN PLANT BIOLOGY 2010; 13:706-13. [PMID: 20851666 DOI: 10.1016/j.pbi.2010.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/06/2010] [Accepted: 08/25/2010] [Indexed: 05/08/2023]
Abstract
Chemical genomics is relatively new to plant biology in academia; however, the ability of this approach to present novel discoveries is being demonstrated clearly. One particularly suitable application of this approach is plant endomembrane trafficking. The rapid and dynamic nature of vesicular trafficking plus genetic redundancy has hampered effective study of this complex network. The ability of small molecules to act quickly to inhibit or arrest vesicular trafficking should permit the association of specific vesicles, especially endosome compartments, with their cargoes, particularly those destined for the plasma membrane. This approach and the large target space presented by the endomembrane trafficking network require the discovery of many new bioactive molecules. Advances in high-throughput chemical screening in plants are making this a reality. However, successful chemical genomic approaches in plants must be coupled with improvements in automated microscopy, image analysis, and target identification. In addition, the ability to correlate specific molecules with complex phenotypic data will be crucial. The data obtained from these experiments will be composed of a matrix of intracellular markers displaying complex chemically induced phenotypes as well as whole plant and perhaps data generated by genomics, proteomics, and metabolomics. In this manner, it should be possible to view endomembrane trafficking and its interactions as a systems-based network.
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Affiliation(s)
- Glenn R Hicks
- Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
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23
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Abstract
Chemical genomics (i.e., genomics-scale chemical genetics) approaches are based on the ability of low-molecular-mass molecules to modify biological processes. Such molecules are used to affect the activity of a protein or a pathway in a manner that is tunable and reversible. A major advantage of this approach compared to classical plant genetics is the fact that chemical genomics can address loss-of-function lethality and redundancy. Bioactive chemicals resulting from forward or reverse chemical screens can be useful in understanding and dissecting complex biological processes due to the essentially limitless variation in structure and activities inherent in chemical space. An important aspect of utilizing small molecules effectively is to characterize bioactive chemicals in detail including an understanding of structure activity relationships (SARs) and the identification of active and inactive analogs. Bioactive chemicals can be useful as reagents to probe biological pathways directly. However, the identification of cognate targets and their pathways is also informative and can be achieved by screens for genetic resistance or hypersensitivity in Arabidopsis thaliana or other organisms in which the results can be translated to plants. Here, we describe approaches to screen for bioactive chemicals that affect biological processes in Arabidopsis. We will also discuss considerations for the characterization of bioactive compounds and genetic screens for target identification. This should provide those who are considering this approach some practical knowledge of how to design and establish a chemical genomics screen.
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Affiliation(s)
- Lorena Norambuena
- Plant Molecular Biology Laboratory, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
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Robert S, Raikhel NV, Hicks GR. Powerful partners: Arabidopsis and chemical genomics. THE ARABIDOPSIS BOOK 2009; 7:e0109. [PMID: 22303245 PMCID: PMC3243329 DOI: 10.1199/tab.0109] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chemical genomics (i.e. genomics scale chemical genetics) approaches capitalize on the ability of low molecular mass molecules to modify biological processes. Such molecules are used to modify the activity of a protein or a pathway in a manner that it is tunable and reversible. Bioactive chemicals resulting from forward or reverse chemical screens can be useful in understanding and dissecting complex biological processes due to the essentially limitless variation in structure and activities inherent in chemical space. A major advantage of this approach as a powerful addition to conventional plant genetics is the fact that chemical genomics can address loss-of-function lethality and redundancy. Furthermore, the ability of chemicals to be added at will and to act quickly can permit the study of processes that are highly dynamic such as endomembrane trafficking. An important aspect of utilizing small molecules effectively is to characterize bioactive chemicals in detail including an understanding of structure-activity relationships and the identification of active and inactive analogs. Bioactive chemicals can be useful as reagents to probe biological pathways directly. However, the identification of cognate targets and their pathways is also informative and can be achieved by screens for genetic resistance or hypersensitivity in Arabidopsis thaliana or other organisms from which the results can be translated to plants. In addition, there are approaches utilizing "tagged" chemical libraries that possess reactive moieties permitting the immobilization of active compounds. This opens the possibility for biochemical purification of putative cognate targets. We will review approaches to screen for bioactive chemicals that affect biological processes in Arabidopsis and provide several examples of the power and challenges inherent in this new approach in plant biology.
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Affiliation(s)
- Stéphanie Robert
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
- Current address: VIB Department of Plant Systems Biology, University of Ghent, 9052 Ghent, Belgium
| | - Natasha V. Raikhel
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
| | - Glenn R. Hicks
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
- Address correspondence to
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Bassel GW, Fung P, Chow TFF, Foong JA, Provart NJ, Cutler SR. Elucidating the germination transcriptional program using small molecules. PLANT PHYSIOLOGY 2008; 147:143-55. [PMID: 18359847 PMCID: PMC2330302 DOI: 10.1104/pp.107.110841] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The transition from seed to seedling is mediated by germination, a complex process that starts with imbibition and completes with radicle emergence. To gain insight into the transcriptional program mediating germination, previous studies have compared the transcript profiles of dry, dormant, and germinating after-ripened Arabidopsis (Arabidopsis thaliana) seeds. While informative, these approaches did not distinguish the transcriptional responses due to imbibition, shifts in metabolism, or breaking of dormancy from those triggered by the initiation of germination. In this study, three mechanistically distinct small molecules that inhibit Arabidopsis seed germination (methotrexate, 2, 4-dinitrophenol, and cycloheximide) were identified using a small-molecule screen and used to probe the germination transcriptome. Germination-responsive transcripts were defined as those with significantly altered transcript abundance across all inhibitory treatments with respect to control germinating seeds, using data from ATH1 microarrays. This analysis identified numerous germination regulators as germination responsive, including the DELLA proteins GAI, RGA, and RGL3, the abscisic acid-insensitive proteins ABI4, ABI5, ABI8, and FRY1, and the gibberellin receptor GID1A. To help visualize these and other publicly available seed microarray data, we designed a seed mRNA expression browser using the electronic Fluorescent Pictograph platform. An overall decrease in gene expression and a 5-fold greater number of transcripts identified as statistically down-regulated in drug-inhibited seeds point to a role for mRNA degradation or turnover during seed germination. The genes identified in our study as responsive to germination define potential uncharacterized regulators of this process and provide a refined transcriptional signature for germinating Arabidopsis seeds.
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Affiliation(s)
- George W Bassel
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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